Sonic device

ABSTRACT

A sonic device, adapted to be carried by a predatory animal is provided. The device emits a sonic signal either continuously or intermittently with a predetermined interval and duration. The device is controlled by a microprocessor ( 2 ) which is programmable to emit appropriate signals. The device may be temporarily deactivated by a location switch ( 12 ) when the predatory animal enters a defined location, such as a domestic environment, or by an optical switch when the ambient light intensity falls below a particular threshold level. The device includes a waterproof housing and a battery power source and may also include one or more solar panels.

The present invention relates to an animal collar which includes adevice to reduce predation by the subject animal by emitting a signalaudible to its intended prey. In particular, the collar is intended toreduce predation by domestic cats.

Domestic cats are known to have a serious impact on bird populations.Worldwide, cats may have been involved in the extinction of more birdspecies than any other cause except habitat destruction and they arealso contributing to the endangerment of populations of other rare smallmammals. In Britain alone, domestic cats now number 7.2 million and arethought to kill at least 75 million birds annually. In Australia, thecountries 21 million feral and domestic cats are believed to beresponsible for killing 3 million animals per year including 67 nativebird species and in the US, the 60 million domestic cats are estimatedto kill more than 1.4 billion birds each year.

Although cats make affectionate pets, many domestic cats hunt aseffectively as wild predators. However, domestic cats are thought torepresent a greater problem than wild predators for the followingreasons: Firstly, domestic casts are protected from disease, naturalpredation and competition, factors which control numbers of wildpredators. Secondly, domestic cats have a dependable supply of foodprovided by humans and are, therefore, not influenced by changes inpopulations of prey. This means that cats can continue to hunt even rarespecies. Thirdly, unlike many native predators, cat densities are poorlylimited or not limited at all by territoriality. Fourthly, unlike somepredators, a cat's desire to hunt is not suppressed by having anadequate supply of supplemental food. Therefore, a cat's motivation tohunt remains strong even when fed regularly.

Despite being responsible for killing numerous birds and small animals,cats can also perform a useful function as companion pets. They alsohunt pests and vermin which tend to feed at night, for example rats andmice.

It is therefore desired to reduce the number of bird and small animaldeaths caused by cats during the day without reducing a cat'seffectiveness in hunting and killing vermin and pests, such as rats andmice, which generally feed at night.

The following terms used herein are intended to be interpreted in themanner indicated below:

“subject animal” is an animal e.g. a domestic cat, carrying a deviceaccording to the present invention.

“audible” is used to mean capable of being heard by at least one speciesof prey of the subject animal. Sounds which are audible to certainanimals or birds may be outside of the hearing range of human beings.

“Predation” is used to mean the killing of or injury to prey by thesubject animal.

According to a first aspect of the invention there is provided a sonicdevice capable of being carried by a predatory animal, the deviceincluding means for emitting a sonic signal for alerting prey to theanimal's presence.

The sonic signal may be intermittent or it may be continuous.

In embodiments where the sonic signal is intermittent, the delay betweenthe emission of the intermittent sonic signals i.e. the periods when nosignal is emitted, may be variable. Preferably the delay betweenemissions is between 0.5 and 600 seconds, more preferably between 1 and60 seconds and most preferably between 5 and 10 seconds.

The duration of the emitted sonic signal i.e. the period when the signalis being emitted, may also be variable. The emitted sonic signalpreferably lasts between 0.05 and 10000 milli-seconds, more preferablybetween 100 and 1000 milli-seconds and most preferably between 200 and300 milli-seconds. The signal is preferably audible to a wide variety ofpotential prey of the subject animal. In a preferred embodiment thefrequency of the emitted signal is between 300 and 8000 hertz. Thedevice preferably includes means to vary the frequency of the emittedsignal. More preferably, the device further includes means forgenerating a frequency modulated signal in which the frequency iscontinuously variable in a predetermined manner.

Embodiments of the invention in which the sonic signal is continuous maybe useful for subject animals whose prey includes fast moving animalssuch as bats. In these situations, the sonic signal may be an ultrasonicsignal i.e. a sonic signal having a frequency greater than about 20 kHz.For the purposes of this invention, the term “sonic signal” is intendedto include signals having a frequency in the ultrasound region (i.e.signals having a frequency greater than about 20 kHz).

The device is preferably carried by the animal via an attachment means,more preferably by a collar.

The device is preferably lightweight and more preferably small enough tobe worn by the animal on eg. a collar without interfering with theanimal's normal behaviour, other than its predatory behaviour.

Since the device may be worn permanently by the animal, it shouldpreferably have a rugged construction capable of withstanding vibrationand small impacts without impairing the performance of the device andmore preferably it should be waterproof. By permanently it is meanteither the lifetime of the animal or the lifetime of the device.

In a preferred embodiment, the device is housed in a housing. Thehousing may be constructed such that it is possible to obtain access tothe device eg. the housing is a two-part construction wherein the twoparts are releasably coupled to each other. Alternatively it may beconstructed such that it is not possible to obtain access to the devicewithout breaking the housing. That is to say the housing and device maybe constructed as a disposable unit.

The device may be battery powered. The battery lifetime is preferably 1year or more. In order to achieve this long lifetime the components ofthe device are preferably low power consumption components. To improvebattery lifetime, the device may include one or more solar panels and abattery capable of being recharged by energy converted from solar energyby the or each of the solar panels.

The distance at which the signal is audible to a species of prey of thesubject animal is preferably 3 meters or more.

The sonic signal may mimic an alarm or distress call of a particularspecies of prey. This type of signal is useful for protecting specificendangered or rare animals or birds which are at risk from attack by thesubject animal. Alternatively, the sonic signal may be a complexsynthesised sound. By this it is meant that the alarm or distress callis electronically generated. Where the signal is an alarm or distresscall of a particular animal or bird, or a complex synthesised sound, itmay be recorded and stored in the device, for example in a memory chip.The stored alarm or distress call or complex synthesised sound may becapable of being repeatedly emitted as the sonic signal of the device.

The emitted sonic signal preferably does not cause distress to thesubject animal wearing the device or interfere with its normalbehaviour, except of course its predatory behaviour.

In a preferred embodiment the subject animal is a domestic cat. Domesticcats spend part of their time within a domestic environment e.g. in itsowner's home. To prevent the sonic signal of the device becoming anuisance within the domestic environment, the device may be deactivatedwhen the animal e.g. cat is within a predetermined area. To achievethis, the device preferably includes switching means which is capable ofactivating the device outside of the predetermined area and deactivatingit when the animal is within the predetermined area.

The switching means may be operable as the animal passes through apredetermined opening of the domestic environment e.g. a cat flap. Suchswitching means may include a Hall Effect sensor within the device whichis sensitive to a particular magnetic field generated in the proximityof the cat flap.

As an alternative to the switching means being operable as the animale.g. a cat passes through a predetermined opening of the domesticenvironment e.g. a cat flap, the switching means may be sensitive to aninductive loop transmitter system wherein an inductive loop may be wiredaround the domestic environment and is driven electronically or simplyby a loop amplifier powered e.g. by mains electrical supply.

A further alternative switching means includes an RF signal receiverresponsive to RF signals transmitted from an RF transmitter locatedwithin the domestic environment. The device is deactivated when the RFreceiver of the device carried by the animal comes within range of theRF signals transmitted by the transmitter and the device is activatedwhen the RF receiver no longer receives the RF signals. The RFtransmitter is preferably mains powered, but it could alternatively bebattery powered, battery and mains powered, solar powered or powered byany other suitable means. The RF transmitter may be portable such thatit may be connected to a suitable mains electrical supply withindifferent predetermined areas. The transmitting range of the RFtransmitter may be variable such that it can cover differently sizeddomestic environments.

A yet further alternative switching means includes an ultrasonic signalreceiver responsive to ultrasonic signals such that the switching meansmay activate or deactivate the device in response to the receivedultrasonic signals.

The RF receiver in the device may be modified so that it can receiveradio broadcasts from an alternative or a second source, different tothe RF transmitter which is in or near to the domestic environment. TheRF signals broadcast by the second source are preferably capable ofbeing converted into sonic signals emitted by the device. For example, aspecific animal or bird distress or alarm call, or a series of these,may be broadcast as an RF signal by the second source and received bythe RF receiver in the device. The received RF signal from the secondsource is then converted into the specific distress or alarm call, whichis emitted by the device either in place of the predetermined sonicsignal or in addition to the predetermined sonic signal. This modifieddevice is particularly advantageous in situations where a specific rareanimal or bird is introduced or reintroduced into an area e.g. a smallisland. The alarm or distress call of this animal or bird can be encodedin the form of an RF signal which is transmitted throughout the area,whereupon any predators in the area who are carrying a device accordingto this preferred embodiment of the invention will receive thebroadcast. The device will then process the broadcasted RF signal andemit a sonic signal corresponding to that encoded in the RFtransmission, thereby reducing predation by the subject animal of thespecific animal or bird, whose alarm or distress call was encoded in theRF transmission. Alarm or distress calls of more than one animal or birdmay be encoded and broadcast.

To enable the subject animals e.g. cats to continue to hunt pests andvermin at night, the device preferably includes an optical switch. Thisactivates the device during daylight hours and deactivates it during thenight. It is known that in bright sunlight the light intensity is about20,000 lux. This falls to less than about 10 lux during the night. Assuch, the optical switch preferably deactivates the device when thelight intensity level falls below a preselected threshold limit e.g.below about 100 lux. In a preferred embodiment, the optical switchdeactivates the device when the light intensity level is about 10 lux orless. It may be possible to vary the preselected threshold limit.

In a preferred embodiment, the device is carried by the subject animalvia attachment means e.g. a collar, which includes light emitting orreflecting markings to provide a visual warning of the subject animalspresence in addition to the sonic warning emitted by the device. Sincebirds for example can detect light in the UV region of theelectromagnetic spectrum, the markings preferably emit and/or reflect UVlight.

The sonic emissions of the device may interfere with the naturalinteractions between two or more subject animals e.g. during mating. Toovercome any such unwanted interference, the device may include aproximity sensor which is capable of temporarily deactivating the devicewhen it detects another such device in close proximity to it. That is tosay when two subject animals both of which are wearing sonic devices arein close proximity to each other, both of the devices may be temporarilydeactivated.

A second aspect of the present invention provides a method of reducingpredation by a subject animal, the method including fitting the subjectanimal with a device according to the first aspect of the invention.Preferably, the device is fitted via attachment means, more preferablyvia a collar.

A third aspect of the present invention provides use of a sonic deviceaccording to the first aspect of the invention to alert prey to thepresence of a subject animal.

A fourth aspect of the invention provides an attachment means forwearing by an animal, the attachment means carrying a device accordingto the first aspect of the invention.

A fifth aspect of the invention provides an animal wearing a deviceaccording to the first aspect of the invention. Preferably the device iscarried by an attachment means.

An embodiment of the present invention will now be described, by way ofexample only, with reference to the accompanying drawing in which:

FIG. 1 shows a schematic representation of a device of the presentinvention.

The device as represented in FIG. 1 is housed in a lightweightwaterproof two piece plastic housing (not shown) which is a attached toa cat collar. It is controlled by a PIC 12C672 microcontroller 2commercially available from Arizona Microchip (supplied by MicrochipTechnology Inc, Chandler, Ariz.). A light sensor 12 (optical switch partnumber BPX79 available from Plusopto) is connected via an amplifier 8 tothe microcontroller 2. The microcontroller 2 includes an internalcomparator 16 which compares an amplified input signal from the lightsensor 12 with a predetermined threshold limit. The threshold limit isset to be equivalent to an ambient light level of 100 lux. When thelight sensor detects an ambient light level intensity below 100 lux themicrocontroller is placed in a sleep mode. The amplifier 8 is a commonlyavailable electronic component. It is preferably a low power consumptionamplifier. The light sensor arrangement allows for example the cat tohunt at night but reduces effective predation during the day. An RFreceiver 6 is connected to the microcontroller 2 to determine whether ornot the subject animal is within the domestic environment. The RFreceiver 6 receives radio signals via an aerial 14 and converts the RFsignals to electrical signals which are processed by the microcontroller2. The RF signal is broadcast by an RF transmitting base station (notshown) connected to a mains electrical supply within a building. The RFsignal is broadcast on a licence-free wavelength. The RF signal has aneffective transmission range of about 25 to 30 meters within thebuilding and has a diminishing range outside the building. The RFreceiver 6 merely detects the presence of the RF transmission. That isto say it simply has a carrier detect function. Both the RF transmittingbase station and RF receiver 6 are commonly available components andneed not be described in detail herein. The sonic signal data is storedon an external 8 pin serial EEPROM device 10 connected to themicrocontroller 2. The microcontroller 2 selectively energises apiezoelectric sounder 4 (a PCB buzzer, part number KU58N available fromMaplin) to emit a 4 kHz sonic signal. A skilled person will appreciatethat different sonic signals may be emitted in accordance with the datastored on the EEPROM device 10. If the data table for the sonic signalis small, the EEPROM device 10 may not be necessary and the data tablefor the sonic signal stored in a memory location or locations of themicrocontroller 2.

The delay between emission of the sonic signals is 7 seconds and thesignals have a duration of 250 milliseconds.

The device is powered by a 3 volt lithium battery (not shown) suchbatteries are commonly available, for example part No. P199 from Digikeywhich is a 255 milliamp hour battery.

The present invention has been disclosed above with reference to onepresently preferred exemplary embodiment. However, the invention is notto be construed as being limited to that which has been specificallydescribed and/or illustrated and various modifications may be made aswill be apparent to the person skilled in the art without departing fromthe scope of the invention as will be defined in the claims.

What is claimed is:
 1. A sonic device adapted to be carried by apredatory animal, the device including means for emitting a sonic signalfor alerting prey to the animal's presence, characterized in that thedevice further includes a suspension means to suspend emission of thesonic signal when the device is within a predetermined area.
 2. A sonicdevice according to claim 1 wherein the sonic signal is an intermittentsignal.
 3. A sonic device according to claim 2 wherein the delay betweensonic signal emissions is 0.5 to 600 seconds.
 4. A sonic deviceaccording to claim 3 wherein the duration of the sonic signal emissionis 0.05 to 10000 milliseconds.
 5. A sonic device according to claim 1wherein the frequency of the emitted sonic signal is 300 to 8000 Hz. 6.A sonic device according to claim 1 wherein the device includes means tovary the frequency of the emitted sonic signal.
 7. A sonic deviceaccording to claim 1 wherein the device includes means for generating afrequency modulated signal.
 8. A sonic device according to claim 7wherein the frequency is continuously variable in a predeterminedmanner.
 9. A sonic device according to claim 1 wherein the device iscarried by the animal via an attachment means.
 10. A sonic deviceaccording to claim 9 wherein the attachment means is a collar adapted tobe worn by the animal.
 11. A sonic device according to claim 1 whereinthe device is housed in a housing.
 12. A sonic device according to claim11 wherein the housing is waterproof.
 13. A sonic device according toclaim 11 wherein the housing is a two-part construction wherein the twoparts are releasably coupled to each other.
 14. A sonic device accordingto claim 11 wherein the housing is a one-piece construction whereby thedevice is formed as a disposable unit.
 15. A sonic device according toclaim 1 wherein the device is battery powered.
 16. A sonic deviceaccording to claim 15 wherein the device further includes one or moresolar panels and the battery is capable of being recharged by electricalenergy converted from solar energy by the or each solar panel.
 17. Asonic device according to claim 1 wherein the emitted sonic signal is analarm or distress call of a predetermined species of prey.
 18. A sonicdevice according to claim 1 wherein the emitted sonic signal is acomplex synthesised sound.
 19. A sonic device according to claim 1wherein the device includes means for storing a recording of the sonicsignal whereby the sonic signal is capable of being repeatedly emitted.20. A method of reducing predation by a subject animal, the methodincluding fitting the subject animal with a device according to claim 1.21. A sonic device according to claim 1 wherein the suspension meansincludes a location switch capable of activating the device outside ofthe predetermined area and deactivating it when the device is within thepredetermined area.
 22. A sonic device according to claim 21 wherein thelocation switch includes an RF signal receiver and the predeterminedarea is defined by RF signals having a predetermined effective rangetransmitted by an RF transmitter, the RF signal receiver beingresponsive to the RF signals transmitted by the RF transmitter such thatthe device is deactivated when the RF receiver of the device comeswithin the effective range of the transmitted RF signals and the deviceis activated or reactivated when the RF receiver is no longer capable ofdetecting the transmitted RF signals.
 23. A sonic device according toclaim 1 wherein the device includes an optical switch.
 24. A sonicdevice according to claim 23 wherein the optical switch deactivates thedevice when the light intensity is below a predetermined value andactivates or reactivates the device when the light intensity is abovethe predetermined value.
 25. A sonic device according to claim 24wherein the predetermined light intensity value is 10 lux.